As today, my external monitor is not detected any more by my Ubuntu 17.10 laptop :(

  • I know the monitor and cable are working correctly since it works on a different laptop.

  • Settings -> Devices -> Displays shows only the laptop screen.

  • No matter if I log in with wayland or xorg, same result.

  • Keyboard key to switch display mode does nothing (apparently)

xrandr output:

Screen 0: minimum 320 x 200, current 1920 x 1080, maximum 8192 x 8192
XWAYLAND0 connected 1920x1080+0+0 (normal left inverted right x axis y axis) 350mm x 190mm
   1920x1080     59.96*+

lspci | grep -iE "display|vga" ouptut:

00:02.0 VGA compatible controller: Intel Corporation HD Graphics 5500 (rev 09)
09:00.0 Display controller: Advanced Micro Devices, Inc. [AMD/ATI] Topaz XT [Radeon R7 M260/M265 / M340/M360 / M440/M445] (rev ff)

Any ideas?

  • Using 17.10 actually, "16.10" was a typo. – DavidEG Jan 7 '18 at 15:28
  • Your question was closed as being about an unsupported Ubuntu version, but your answer suggests that the problem now can't be reproduced, so I don't think there is any benefit in reopening it at this stage. – guntbert Jan 7 '18 at 19:50
  • Fair enough. For what it's worth, looks like my bios has been misbehaving due to bugs.launchpad.net/ubuntu/+source/linux/+bug/1734147. – DavidEG Jan 8 '18 at 11:27

Well, not sure how this fixed it but I went to the bios and change display from "auto detect" to "external hdmi", then started to work again.

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